crossopterygian

noun

cros·​sop·​ter·​yg·​ian ˌkrȯ-ˌsäp-tə-ˈri-j(ē-)ən 

: any of a subclass (Crossopterygii) of bony fishes (such as a coelacanth) that have paired fins suggesting limbs, that may be ancestral to the terrestrial vertebrates, and that are mostly extinct

called also lobe-fin

crossopterygian adjective

Word History

Etymology

New Latin Crossopterygii, subclass name, from Greek krossoi fringe + pterygion, diminutive of pteryg-, pteryx wing, fin; akin to Greek pteron wing — more at feather

First Known Use

1861, in the meaning defined above